Liam Fox called for public spending to be frozen for five years as he dodged questions over whether he was positioning himself to challenge for the Tory leadership amid rumours David Cameron's position is under threat.

In recent days Theresa May has emerged as a leading candidate to succeed the prime minister. The home secretary fuelled speculation she had her eyes on the top job over the weekend when she made a wide ranging speech on the future direction of the party that strayed way beyond her departmental brief.

Asked if he was preparing for a future leadership battle with May, Fox lamented the "sheer inevitability" of the "depressing" question. However the leading member of the Tory right failed to dismiss the suggestion.

"What I think the Conservative Party needs to do is focus on its agenda and the obsession with personality at the expense of agenda is not sensible for any political party especially not the county's most important one," he said.

Asked again by BBC Radio 4's World at One programme after his speech, Fox said refused to rule out standing for the Tory leadership and said "far too much of our politics is dominated by personalities and not enough by a sensible debate about policy".

"I think there is no chance of us having a leadership election in the Conservative Party before the election, I think that would be madness," he said.

Pressed on whether he would consider standing for the leadership in the future he added: "In ten years time if David Cameron stands down I'll see how I'm holding up at that point."

In a well trailed speech in Westminster on Monday morning, the former defence secretary said the principle of universal benefits should be ended and attacked the "drug of welfare addiction" that he said had ensnared even the "affluent middle classes".

"I believe that the country will be at its best when the government is small and people are left to enjoy the fruits of their own labour," he said. "I believe that in leaving money in people’s pockets, economic activity will follow. People will buy houses, invest for their future or just go shopping."

"How did we ever get to a situation where those earning £60,000 were receiving state benefits, where your household income could be bigger on welfare than the working family next door or where those on low pay subsidised cold weather payments for pensioners living on the Costa del Sol."

Fox also criticised the coalition's commitment to protect certain departments from cuts, including health. He said while total spending should be frozen, the government should be allowed to move money around as it saw fit depending on priorities.

Fox has an unlikely ally in his criticism of ring-fencing in Lib Dem business secretary Vince Cable, who told BBC Radio 4's Today programme this morning that protecting some departmental budgets was not "sensible" in the long term.

With George Osborne's Budget just over a week away Fox said he was setting out a platform the party should use to fight the 2015 election. "What I think I'm doing is setting out a fairly mainstream conservative economic agenda, while one or two of these measures might be worth considering by the chancellor in his forthcoming budget, what I am doing is setting out a wider agenda for the longer term as we start to think about our next election manifesto."

"It is up to the electorate to ensure they don't hobble themselves with high-spending high-taxing government that will make their children disadvantaged in relation to them.

"People are unwilling to suffer austerity today for its own sake but we nee to make it clear this is to give the next generation a better start, there is an emotional argument that can be made that has not been."